1. Field of the Invention
This invention relates to a hybrid rechargeable battery which is of the type that includes both high power and high energy density lithium cells, with an exterior smart circuit interface, and an exterior charger.
2. Description of the Prior Art
It has been recognized that there is a need for a high power battery that can repeatedly deliver maximum electrical current for a longer time than currently available capacitors. Batteries that incorporate high power cells and deliver relatively high maximum electrical current for a longer time than a capacitor are available, but the duration of their operation is limited. High energy density cells store and deliver a greater amount of electrical energy, but at lower electrical current than high power cells.
U.S. Pat. No. 5,998,0522 of Yamin, discloses a hybrid battery comprising a primary cell and rechargeable (secondary) cell connected in parallel. The suggested rechargeable cell is a lithium-ion cell, and the primary cell is lithium-thionylchloride based or other oxyhalide based. This system has a disadvantage of not being a rechargeable unit with high cost of the primary cell therein, and the whole battery has to be disposed of after use. In this proposed design, both cells in the battery must be replaced with a new battery after full discharge of the primary cell, which is very expensive.
Another combination, which is known is a hybrid system having a capacitor and a primary battery is manufactured by Tadiran Batteries, Kiryat Ekron, Israel, and Port Washington, N.Y. Similar cost disadvantages occur, and additionally the capacitor provides only very short pulsing capability.
Another combination hybrid, known in military applications, is the use of a primary zinc-air battery with a lithium-ion battery connected thereto by a cable. Again the cost of the primary battery replacement is high. Several zinc-air cells are connected in series to match the voltage of the lithium-ion battery. Only the primary battery is disposed of after discharge, due to the disconnectable cable.
In cases of rechargeable cells, the lithium-ion cells described above are of standard design, and not designed for very high rates of discharge, as described in the present invention.
As an example, my prior art published application Ser. No. 09/911,036 entitled: “Manufacturing Method and Structure of Electrodes For Lithium Based Electrochemical Devices”, describes high power electrodes, and my prior art application Ser. No. 10/119,220, entitled: “Method of Automated Hybrid Lithium-Ion Cells Production and Method of the Cell Assembly and Construction”, describes high energy density lithium-ion cells. These cells are “hybrid” in the sense that they combine the advantages of lithium-ion polymer cells, and lithium-ion cells with liquid electrolyte. The same construction and method of assembly may apply to high power cells, having thinner electrodes and full width collector tabs.
My U.S. Pat. No. 5,811,959 describes an interface device and charger for efficient and safe charging, and discharging of multi-celled batteries, or packs of batteries, and which device is preferably external to the battery.
In the present invention, the combination of the high power and high energy density rechargeable cells provides a rechargeable battery, that delivers high maximum electrical current over time with the high power cells being recharged by the high energy density cells, preferably in parallel, and all cells can be recharged through an interface device by a charger than can recharge both types of cells, and preferably in parallel. This arrangement provides a rechargeable battery that meets both high power and high-energy electrical requirements.